Polycrystalline diamond compact (PDC) cutting element having multiple catalytic elements

ABSTRACT

A polycrystalline diamond compact useful for wear, cutting, drilling, drawing and like applications is provided with a first diamond region remote from the working surface which has a metallic catalyzing material and a second diamond region adjacent to or including the working surface containing a non-metallic catalyst and the method of making such a compact is provided. This compact is particularly useful in high temperature operations, such as hard rock drilling because of the improved thermal stability at the working surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/614,330 filed Nov. 6, 2009, now U.S. Pat. No. 7,950,477, entitledPOLYCRYSTALLINE DIAMOND COMPACT (PDC) CUTTING ELEMENT HAVING MULTIPLECATALYTIC ELEMENTS, which is a continuation of U.S. patent applicationSer. No. 11/210,292 filed Aug. 24, 2005, now U.S. Pat. No. 7,635,035,entitled POLYCRYSTALLINE DIAMOND COMPACT (PDC) CUTTING ELEMENT HAVINGMULTIPLE CATALYTIC ELEMENTS, the disclosures of each of which areincorporated by reference herein in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to superhard polycrystalline cutting elementsused for wear, drawing and other tool applications where superhardproperties are useful. More specifically, this invention relates to suchsuperhard polycrystalline cutting elements that make use ofpolycrystalline diamond regions for the cutting or wear surface.

2. Description of Related Art

A wide variety of polycrystalline diamond compacts (PDC) are well knownin the art. Generally, these prior devices do not incorporate athermally stable catalytic element in the region adjacent to the cuttingsurface, that therefore prior PDC devices tend to have a mismatch inthermal expansion that can cause the interstitial metal to exert a highstress on the diamond lattice, which in turn can lead to fracture of thediamond-to-diamond bonds and subsequent premature failure of thecompact. Further, prior PDC devices tend to incorporate a non-thermallystable catalytic element that readily dissolves carbon from the diamondsurface at elevated temperatures, thereby, leading to the conversion ofdiamond to graphite, which in turn leads to premature failure of thecompact.

Common PDCs are formed by subjecting diamond or other superhardparticles (such as Cubic Boron Nitride (CBN) and the like) tohigh-temperatures and high pressure in the presence of a metalliccatalyst to form a polycrystalline matrix of inter-bonded particles.This bonding process is typically referred to as “sintering.” Themetallic catalyst typically remains in the polycrystalline diamondmatrix, although some PDCs have used leaching to remove some or all ofthe catalyst. Well known PolyCrystalline Diamond (PCD) elementstypically consist of a facing table of polycrystalline diamondintegrally bonded to a substrate of a less hard material, such ascemented tungsten carbide. This material is often referred to as aPolycrystalline Diamond Compact (PDC). PDC is commonly used in down holetools; such as drill bits (including drag bits, also called fixed cutterbits; percussion bits; rolling cone bits, also called rock bits),reamers, stabilizers and tool joints.

Thermal stability in a PDC has become known as important for itsrelationship to the successful use of the compact's use in hard rockdrilling applications. High temperatures are generated at the leadingedge of the PDC tool while cutting rock. These high temperatures cancause premature failure of the tool via several mechanisms, two of whichare graphitization of the polycrystalline diamond in contact with theinterstitial metallic catalyst and thermal expansion of the interstitialmetallic catalyst. In the graphitization mechanism, carbon is readilydissolved from the diamond surface as the temperature of the cutting tipincreases above about 450° C. This dissolving of the carbon is due tothe increased saturation level of carbon in the metallic catalyst withincreasing temperature. The dissolved carbon takes the form of graphitesince the PCD tool operates outside of the thermodynamic stabilityregion of diamond. In the thermal expansion mechanism, this thermalexpansion of the metallic catalyst is several times greater than that ofdiamond for a given increase in temperature. The mismatch in thermalexpansion causes the interstitial metal to exert a high stress on thediamond lattice. These stresses can lead to a fracture ofdiamond-to-diamond bonds at or above about 700° C. and subsequentpremature failure of the compact.

The most common method of improving the thermal stability of PDC is tofully or partially remove the metallic catalyst from the diamondlattice. Some of the following listed references disclose this techniquein some detail. Material with the metallic catalyst removed from theentire sintered diamond body is commonly known as Thermally StablePolycrystalline (TSP) diamond.

Although the following references may not necessarily qualify as “priorart,” the reader is referred to these following U.S. Patent documentsfor general background material. Each of these patent references ishereby incorporated by reference in its entirety for the materialcontained therein.

U.S. Pat. No. 3,745,623 describes diamond tools and superpressureprocesses for the preparation thereof, wherein the diamond content ispresent either in the form of a mass comprising diamond crystals bondedto each other or of a thin skin of diamond crystals bonded to eachother.

U.S. Pat. No. 4,224,380 describes a compact for tools, such as cutting,drilling and shaping tools that consists essentially of self-bondedabrasive particles.

U.S. Pat. No. 4,311,490 describes a process for preparing a compositecompact wherein a mass of abrasive crystals, a mass of metal carbide,and a boding medium are subjected to a high-temperature/high pressureprocess for providing a composite compact.

U.S. Pat. No. 4,333,986 describes a diamond sintered compact whereindiamond crystal particles are uniformly oriented in a particulardirection and the method for producing the same.

U.S. Pat. No. 4,518,659 describes a high pressure/high temperaturecatalyst sweep through process for making diamond and cubic boronnitride compacts that adds an intermediate metal or metal alloy.

U.S. Pat. No. 4,525,179 describes a high pressure/high temperature(HP/HT) process for making diamond or CBN compacts that includes placingpartitions within the crystal mass before HP/HT processing.

U.S. Pat. No. 4,629,373 describes a polycrystalline diamond body with aplurality of faces having enhanced surface irregularities over at leasta portion of at least one of the faces.

U.S. Pat. No. 4,664,705 describes a polycrystalline diamond (PCD) bodywith improved thermal stability which comprises a PCD body which has hadat least one of its previously empty pores infiltrated by a siliconcontaining alloy.

U.S. Pat. No. 4,694,918 describes a percussion rock bit that comprises asteel body having a means for connection to a drill string at one endand having a plurality of inserts at the other end for crushing rock atthe bottom of a hole being drilled.

U.S. Pat. No. 4,738,689 describes a polycrystalline compact ofself-bonded diamond particles having a network of interconnected emptypores dispersed throughout.

U.S. Pat. No. 4,798,026 describes a thermostable abrasive diamondproduct that includes a compact formed of diamond grains representingmore than 80% by volume of the compact, each grain being bonded directlyto its neighbors so as to form a polycrystalline structure.

U.S. Pat. No. 4,871,377 describes a composite compact adapted forhigh-temperature uses, such as a cutter on a rotary drill bit, whichincludes a relatively thick table of diamond or boron nitride particleswith a strong, chemically inert binder matrix and a thin metal layerbonded directly to the table in a HP/HT press.

U.S. Pat. No. 4,874,398 describes a process for producing a diamondcompact having a compressive strength of at least 10 kbars.

U.S. Pat. No. 4,906,528 describes a cutting element of flat shapesuitable for use as a drill tip that comprises a central abrading bladecontaining more than 80% vol. CBN sandwiched between two lateral supportlayers.

U.S. Pat. No. 4,948,388 describes a diamond compact comprised of 60-95volume percent of diamond crystals which have been plastically deformedso that they form a rigid framework structure in which contacts betweenthe diamond crystals occur over surfaces arising from plasticdeformation of the diamond crystals during formation of the compactunder pressure and temperature conditions within the graphite stabilityfield.

U.S. Pat. No. 4,985,051 describes a diamond compact composed of 60-95volume % diamond crystals plastically deformed into a closely packed,rigid structure with contacts between the diamond crystals over extendedmating surfaces arising from the plastic deformation.

U.S. Pat. No. 5,009,673 describes a method for manufacturing apolycrystalline sandwich compact comprising a polycrystalline diamond orCBN core interposed between outer support layers.

U.S. Pat. No. 5,011,509 describes a compact blank for use in operationsthat require very high abrasion resistance and a thermally stablecutting edge.

U.S. Pat. No. 5,011,514 describes superabrasive cutting elements, backedcompacts and methods for their manufacture wherein metal-coatedsuperabrasive particles are cemented under HPHT conditions.

U.S. Pat. No. 5,127,923 describes an abrasive compact with asubstantially solid body that is provided from a mass of abrasiveparticles, which are bonded together on a particle-to-particle basis.

U.S. Pat. No. 5,151,107 describes superabrasive cutting elements, backedcompacts and methods for their manufacture wherein metal-coatedsuperabrasive particles are cemented under HPHT conditions.

U.S. Pat. No. 5,266,236 describes a method for making a thermallystable, dense, electrically conductive diamond compact.

U.S. Pat. No. 5,273,557 describes rotary drill bits and blanks whichretain polycrystalline diamond or CBN compacts, but which do not sufferfrom disadvantages attendant by prior drill designs.

U.S. Pat. No. 5,304,342 describes a sintered product useful forabrasion- and impact-resistant tools and the like, comprising aniron-group metal binder and refractory metal carbide particles, e.g.tungsten carbide, formed in situ during sintering by the exothermicreaction of a carbide-forming refractory metal powder with a carbonsource mixed therewith.

U.S. Pat. No. 5,351,772 describes a substantially polycrystallinediamond compact cutting element for drilling subterranean formations.

U.S. Pat. No. 5,370,195 describes a drill bit that has a means at oneend for connecting the bit to a drill string and a plurality of insertsat the other end for crushing the rock to be drilled.

U.S. Pat. No. 5,435,403 describes a cutting element having asubstantially planar table of superhard material mounted on a substrateor backing.

U.S. Pat. No. 5,590,729 describes a cutting element for a rotary drillbit for subterranean drilling, including a substantially planar table ofsuperhard material having a cutting face and a cutting edge.

U.S. Pat. No. 5,605,198 describes a drill bit employing selectiveplacement of cutting elements engineered to accommodate differing loadssuch as are experienced at different locations on the bit crown.

U.S. Pat. No. 5,769,176 describes a diamond sintered compact having ahigher strength as well as more excellent heat resistance, breakageresistance and corrosion resistance.

U.S. Pat. No. 5,787,022 describes a drill bit employing selectiveplacement of cutting elements engineered to accommodate differing loadssuch as are experienced at different locations on the bit crown.

U.S. Pat. No. 5,959,747 describes a drill bit employing selectiveplacement of cutting elements engineered to accommodate differing loadssuch as are experienced at different locations on the bit crown.

U.S. Pat. No. 5,967,249 describes a cutter for use on a rotary-type dragbit for earth boring, comprising a substantially rectangular diamondtable attached to a substrate.

U.S. Pat. No. 6,021,859 describes a drill bit employing selectiveplacement of cutting elements engineered to accommodate differing loadssuch as are experienced at different locations on the bit crown.

U.S. Pat. No. 6,068,913 describes a PCD/PCBN tool and method for makingthe same that involves the use of an intermediate layer ofpolycrystalline material between a substrate and an outer working layer.

U.S. Pat. No. 6,245,312 B1 describes a superhard carbon material havinga structure comprising structural elements, in the form of tetrahedrons,with groups of carbon atoms in their apices.

U.S. Pat. No. 6,315,065 B1 describes a cutter element for use in a drillbit, comprising a substrate and a plurality of layers thereon.

U.S. Pat. No. 6,401,844 B1 describes a cutter comprising a superabrasivevolume that includes a cutting face portion extending transverselyacross a leading face of a supporting substrate and a contiguous jacketportion extending rearwardly over the supporting substrate along aportion of its side periphery.

U.S. Pat. No. 6,410,085 B1 describes a method of machining apolycrystalline diamond material that includes a matrix of intersticescontaining a catalyzing material and volume close to a working surfacethereof substantially free of catalyzing material.

U.S. Pat. No. 6,435,058 B1 describes a method for use in designingrotary drill bits that comprises determining locations in which cuttersare to be provided.

U.S. Pat. No. 6,443,248 B2 describes a cutter element for use in a drillbit, comprising a substrate and a plurality of layers thereon.

U.S. Pat. No. 6,481,511 B2 describes a rotary drill bit that includescutters arranged in a series of concentric rings.

U.S. Pat. No. 6,544,308 B2 describes a polycrystalline diamond ordiamond-like element with greatly improved wear resistance without lossof impact strength.

U.S. Pat. No. 6,562,462 B2 describes a polycrystalline diamond ordiamond-like element with greatly improved wear resistance without lossof impact strength.

U.S. Pat. No. 6,585,064 B2 describes an earth boring drill bit with asuperhard polycrystalline diamond or diamond-like element with greatlyimproved resistance to thermal degradation without loss of impactstrength.

U.S. Pat. No. 6,589,640 B2 describes a superhard polycrystalline diamondor diamond-like element with greatly improved resistance to thermaldegradation without loss of impact strength.

U.S. Pat. No. 6,592,985 B2 describes a superhard polycrystalline diamondor diamond-like element with greatly improved resistance to thermaldegradation without loss of impact strength.

U.S. Pat. No. 6,601,662 B2 describes a polycrystalline diamond ordiamond-like element with greatly improved resistance to thermaldegradation without loss of impact strength.

U.S. Pat. No. 6,739,214 B2 describes a method of making an earth boringdrill bit having a superhard polycrystalline diamond or diamond-likeelement with greatly improved resistance to thermal degradation withoutloss of impact strength.

U.S. Pat. No. 6,749,033 B2 describes a superhard polycrystalline diamondor diamond-like element with greatly improved resistance to thermaldegradation without loss of impact strength.

U.S. Pat. No. 6,861,098 B2 describes a method for forming a superhardpolycrystalline diamond or diamond-like element with greatly improvedresistance to thermal degradation without loss of impact strength.

U.S. Pat. No. 6,861,137 B2 describes a method for manufacturing apolycrystalline diamond or diamond-like element with greatly improvedresistance to thermal degradation without loss of impact strength.

U.S. Pat. No. 6,878,447 B2 describes a superhard polycrystalline diamondor diamond-like element with greatly improved resistance to thermaldegradation without loss of impact strength.

SUMMARY OF THE INVENTION

It is desirable to provide improved thermal stability in polycrystallinediamond compacts (PDC). It is particularly desirable to provide suchimproved stability by incorporating in the design of the PDC two or morecatalytic elements, at least one of which is a thermally stablecatalytic element and which is incorporated in and/or within the cuttingsurface.

Accordingly, it is an object of one or more embodiments of thisinvention to provide a PDC with two or more catalytic elementsincorporated within the PDC.

It is another object of one or more embodiments of this invention toprovide a PDC with a thermally stable catalytic element incorporatedwithin the PDC.

It is a further object of one or more embodiments of this invention toprovide a PDC with a thermally stable catalytic element incorporatedwithin the region adjacent to the cutting surface of the PDC.

It is a still further object of one or more embodiments of thisinvention to provide a PDC with a metallic catalytic element within afirst volume remote from the working surface and a second non-metallicthermally stable catalyzing material in a second volume adjacent to theworking surface.

It is a further object of one or more embodiments of this invention toprovide a PDC where the catalyzing element in the first volume remotefrom the working surface consists of a metallic material selected fromelements of Group VIII of the periodic table, namely Fe, Co, Ni, Ru, Rh,Pd, Os, Ir and Pt.

It is a further object of one or more embodiments of this invention toprovide a PDC where the catalyzing element in the first volume isselected from a transition metal in the group of Mn, Cr and Ta.

It is a further object of one or more embodiments of this invention toprovide a PDC where the catalyzing element in the first volume is abinary system (of alloys or mixtures) where at least one component isselected from carbide formers from Groups IVB, VB, VIB of the periodictable (namely Ti, Zr, Hf, V, Nb, Mo, W) and the other component is anelement from Group IB: Cu, Ag and Au.

It is a further object of one or more embodiments of this invention toprovide a PDC where the catalyzing element in the second volume includesphosphorous.

It is a further object of one or more embodiments of this invention toprovide a PDC where the catalyzing element in the second volume includesone or more alkali earth carbonates (one or more alkaline and alkalineearth) namely: Li₂CO₃; NaCO₃; MgCO₃; CaCO₃; SrCO₃; K₂CO₃; and the like.

It is a further object of one or more embodiments of this invention toprovide a PDC where the catalyzing element in the second volume includesone or more sulfate, namely: Na₂SO₄; MgSO₄; CaSO₄; and the like.

It is a further object of one or more embodiments of this invention toprovide a PDC where the catalyzing element in the second volume includesone or more hydroxides, namely: Mg(OH)₂; Ca(OH)₂; and the like.

It is a further object of one or more embodiments of this invention toprovide a PDC where the catalyzing element in the second volume includesWO₃ and the like.

It is a further object of one or more embodiments of this invention toprovide a PDC where the catalyzing element in the second volume includesboron or boron carbide (B₄C).

It is a further object of one or more embodiments of this invention toprovide a PDC where the catalyzing element in the second volume includesTiC_(0.6).

It is a further object of one or more embodiments of this invention toprovide a PDC where the catalyzing element in the second volume includesiron oxide or double oxide, namely: FeTiO₃; Fe₂SiO₄; Y₃Fe₅O₁₂; and thelike.

It is a further object of one or more embodiments of this invention toprovide a PDC where the catalyzing element in the second volume caninclude a metal selected from germanium, copper or zinc, of whichgermanium is thermally stable.

It is a further object of one or more embodiments of this invention toprovide a PDC where the catalyzing element in the second volume includesone or more buckminsterfullerenes.

It is an object of one or more embodiments of this invention to providea method for making a polycrystalline diamond element that has a workingsurface, a first volume remote from the working surface that contains ametallic catalyzing material, and a second volume adjacent to theworking surface that contains a non-metallic catalyzing material.

It is a still further object of one or more embodiments of thisinvention to provide a method for making a polycrystalline diamondelement where the catalyzing element in the first volume is supplied bya substrate material in contact with the first volume during HighTemperature—High Pressure sintering.

It is a still further object of one or more embodiments of thisinvention to provide a method for making a polycrystalline diamondelement where the catalyzing element in the first volume is mixed withsuperhard particles prior to High Temperature—High Pressure sintering.

It is a still further object of one or more embodiments of thisinvention to provide a method for making a polycrystalline diamondelement where the catalyzing element in the second volume is mixed withsuperhard particles prior to High Temperature—High Pressure sintering.

It is a still further object of one or more embodiments of thisinvention to provide a method for making a polycrystalline diamondelement where the second volume is formed after the HighTemperature—High Pressure sintering process.

It is another object of one or more embodiments of this invention toprovide a process for making a polycrystalline diamond element thatincludes a body with a working surface, a first volume of the bodyremote from the working surface that contains a metallic catalyzingmaterial and a second volume of the body adjacent to the working surfacethat contains a non-metallic catalyzing material, where the metalliccatalyst is removed from the second volume after High Temperature—HighPressure sintering and where the non-metallic catalyst is inserted intothe interstitial spaces between the bonded superhard particles.

It is a further object of one or more embodiments of this invention toprovide a process for making a polycrystalline diamond element where themetallic catalyzing material is removed from the second volume byleaching.

It is a further object of one or more embodiments of this invention toprovide a process for making a polycrystalline diamond element where themetallic catalyzing material is removed from the second volume byelectrical discharge.

It is a further object of one or more embodiments of this invention toprovide a process for making a polycrystalline diamond element where themetallic catalyzing material is removed from the second volume bymechanical means.

It is a further object of one or more embodiments of this invention toprovide a process for making a polycrystalline diamond element where thenon-metallic catalyzing material is reintroduced in an oven cycle.

It is a further object of one or more embodiments of this invention toprovide a process for making a polycrystalline diamond element where thenon-metallic catalyzing material is reintroduced in a second HighTemperature—High Pressure process step.

It is a further object of one or more embodiments of this invention toprovide a process for making a polycrystalline diamond element where thenon-metallic catalyzing material is reintroduced by a solvent.

It is a further object of one or more embodiments of this invention toprovide a process for making a polycrystalline diamond element where thenon-metallic catalyst is a material reintroduced by a gas phase/plasmatechnique.

It is a further object of one or more embodiments of this invention toprovide a process for making a polycrystalline diamond element where thenon-metallic catalyst is a material that is reintroduced by a vacuummelt technique.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of thespecification, illustrate present preferred embodiment(s) of theinvention known to the inventors. Some, although not all, alternativeembodiments are described in the following description.

In the drawings:

FIG. 1 is a section view of a compact of this invention.

FIG. 2 is a processing flow chart of the processing or method steps ofthe manufacture of the compact of this invention.

FIG. 3 is a processing flow chart of and alternative of the processingor method steps of the manufacture of the compact of this invention.

FIG. 4 shows a representative bit employing the compacts of thisinvention.

Reference will now be made in detail to the present preferredembodiment(s) of the invention, an example of which is illustrated inthe accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION

The polycrystalline diamond compact (PDC) of this invention ismanufactured so as to incorporate two or more different catalyticelements. A traditional metallic catalytic element is used in a regionor volume of the polycrystalline diamond layer adjacent to the cementedcarbide substrate. Generally, this metallic catalyst is readily suppliedby the substrate during the high temperature/high pressure (HT/HP)sintering process step, where a strong metallurgical bond is createdbetween the polycrystalline diamond layer and the substrate. One of theimportant and novel features of this invention is the incorporation anduse of a thermally stable non-metallic catalytic element in the regionor volume of the polycrystalline diamond layer adjacent to the workingor cutting surface, in addition to the metallic catalyst provided in thevolume of the polycrystalline diamond layer adjacent to the cementedcarbide substrate. For the purposes of this disclosure, polycrystallinediamond should be considered as both commonly known diamond in apolycrystalline form and cubic boron nitride in a polycrystalline form.Also, typically the substrate region or volume is composed of a cementedtungsten carbide composition, also referred to as WC.

FIG. 1 shows a cross-section view representation of the compact 101 ofthis invention with the three designated regions: namely the substrateregion 101; the first polycrystalline diamond layer 102; and the secondpolycrystalline diamond layer 103. The working or cutting surface 104 isshown along the top and side of the second polycrystalline diamond layer103. The first polycrystalline diamond layer 102 is shown adjacent tothe substrate 101 and remote from the working surface 104. Duringmanufacturing, the sintering using a high temperature/high pressure(HT/HP) press causes a metallic catalytic element, typically cobalt, inthe substrate to dissolve or liquefy and then to sweep through thediamond layer 102 thereby providing for the growth of sintered diamondbonds between the diamond grains of the polycrystalline diamond andforming a solid compact of the substrate and the polycrystalline diamondlayer 102. The catalytic elements typically used in the sintering aregenerally the same catalytic elements necessary for the conversion ofgraphite to diamond in the high temperature/high pressure (HT/HP)process. Most often metallic elements from Group VIII (primarily Fe, Niand/or Co) in the periodic table are used for this sintering process,although other metallic catalysts can be used with or substituted forthe sintering catalyst without departing from the concept of thisinvention. These alternative metallic catalysts include, but are notnecessarily limited to, Group VIII elements, namely: Fe, Co, Ni, Ru, Rh,Pd, Os, Ir and Pd; Transition metals, namely: Mn, Cr and Ta; and Carbideformers from Groups IVB, VB, VIB, namely: Ti, Zr, Hf, V, Nb, Mo and W,alloyed with Group IB elements, namely: Cu, Ag and Au. These metalliccatalysts (primarily Fe, Ni and/or Co) are convenient for themanufacture of PDCs because they are commonly used as binders incemented tungsten carbide, thus the catalytic element necessary for thePCD sintering process is naturally supplied by the substrate during theHT/HP processing, and these metallic catalyst materials tend to form acontinuous metallurgical bond between the PCD layer and the substrate,thereby greatly increasing the strength of the resulting PDC tool.However, these metallic catalyzing elements are not generally consideredto be thermally stable and they generally lead to early failure of thecompact in high temperature use because of their relatively highcoefficients of thermal expansion and their propensity to readilydissolve carbon from diamond at elevated temperatures. It may also bepossible to sinter directly with the non-metallic catalysts, inalternative embodiments of this invention.

Recent discoveries have brought to light the existence of non-metalliccatalytic elements, which have been shown to promote the conversion ofgraphite to diamond at high temperature/high pressure and are thereforesuitable for a HT/HP sintering process step for the production of PCD.These non-metallic catalytic materials include, but are not necessarilylimited to, the following: phosphorous; carbonates, including: Li₂CO₃,Na₂CO₃, MgCO₃, CaCO₃, SrCO₃ and K₂CO₃; sulfates, including: Na₂SO₄,MgSO₄ and CaSO₄; hydroxides, including: Mg(OH)₂ and Ca(OH)₂; WO₃; boroncompounds, including: B and B₄C, TiC_(0.6), Iron oxide and/or doubleoxide, including: FeTiO₃, Fe₂SiO₄, Y₃Fe₅O₁₂ and the like; copper; zinc;germanium; and Buckminsterfullerenes (also known as fullerenes,buckyballs and the like). These elements are generally considered to bethermally stable because they have low coefficients of thermal expansionand do not dissolve carbon from the diamond particles.

Because of their superior thermal stability, these non=metalliccatalytic materials are incorporated into the diamond layer 103 of thecompact 101 of this invention. The non-metallic catalytic materialsprovide for the growth of sintered diamond bonds between the diamondgrains of the polycrystalline diamond of layer 103 and also form astrong bond with diamond layer 102. By incorporating one or more ofthese non-metallic catalyzing materials in to the working surface 104region, which includes both the top and sidewalls of the secondpolycrystalline layer 103, the resulting. PDC compact can provide a morethermally stable cutting edge in use in high temperature contact with arock or otherwise formation. The diamond particles of the second diamondlayer 103 remain integrally bonded with the diamond particles of thefirst diamond layer 102, which in turn remains strongly bonded to thesubstrate via the metallic catalyst in the first diamond layer 102.

FIG. 2 shows the present mode of making or manufacturing the PDC of thisinvention. The working surface polycrystalline diamond material isloaded 201, typically in a can device arrangement for HT/HT processing.The remote working surface polycrystalline diamond material is loaded202, also typically in the can device arrangement for HT/HP processing.In some alternative embodiments, the material for both polycrystallinediamond layers 102, 103 may be loaded together, while in otherembodiments, because of the different characteristics of the desiredcatalysts, they may be loaded in separate steps and may be separated indifferent can components. The substrate material, typically tungstencarbide (WC) is loaded 203, also typically in the can devicearrangement. The can device is completed 204, typically by assemblingthe various components along with potentially other can components asdesired for shaping and structural support. The completed can device isthen subjected to high temperature—high pressure processing 205sufficient to liquefy and/or soften 206 the metal binder in thesubstrate material and to cause this metal binder to sweep 207 throughthe polycrystalline diamond layers 102, 103 thereby sintering 208 thediamond crystals of the polycrystalline diamond layers 102, 103 to thesubstrate 101. The can is removed 209. The compact is finished 212,typically by grinding, shaping, beveling, and polishing as desired. Themetallic catalyzing material is removed 210 from the working surface 104and the second polycrystalline diamond layer 103. Typically, thisremoval 210 is accomplished by leaching, although electrical dischargeand mechanical metallic removal techniques can be substituted withoutdeparting from the concept of this invention. Non-metallic catalyzingmaterial is reintroduced 211 to the working surface 104 and the secondpolycrystalline diamond layer 103. Typically, this non-metallic catalystreintroduction is accomplished by introducing the non-metallic materialthrough a solvent re-precipitation processing step, although alternativeprocessing to reintroduce the non-metallic catalytic material caninvolve a second HT/HP process, an oven cycle, use of a gas phase orplasma and/or a vacuum melt process without departing from the conceptof this invention. At which point the compact is ready for use 213.

FIG. 3 shows an alternative mode of making or manufacturing the PDC ofthis invention. The working surface polycrystalline diamond material isloaded 301, typically in a can device arrangement for HT/HP processing.The loaded material when processed forms a region that contains anon-metallic catalytic element, in the range of 1% to 20% by weight,premixed with the diamond material. The remote working surfacepolycrystalline diamond material is loaded 302, also typically in a candevice arrangement for HT/HP processing. The substrate material,typically tungsten carbide (WC) is loaded 303, also typically in a candevice arrangement. The can device is completed 304, typically byassembling the various components along with potentially other cancomponents as desired for shaping and structural support. The completedcan device is then subjected to high temperature—high pressureprocessing 305 sufficient to liquefy and/or soften 306 the metalliccatalytic element in the substrate material and to cause this metalliccatalytic element to sweep 307 through the polycrystalline diamond layer102, thereby sintering 308 the diamond crystals of the polycrystallinediamond layer 102 to the substrate 101. The metallic catalytic elementis prevented from sweeping through the diamond layer 103 by theinclusion in the diamond layer region of the non-metallic catalyticmaterial. The high temperature—high pressure processing 305 is thenmodified to enable sintering 309 of the polycrystalline diamond layer103 by the non metallic catalytic material mixed therein. Thepolycrystalline diamond layer 103 is thereby sintered to layer 102. Thecan is removed 310. The compact is finished 311, typically by grinding,shaping, beveling and polishing as desired. At which point the compactis ready for use 312.

Alternatively, metallic catalyzing material(s) can be used to sinter theentire polycrystalline diamond table, including both layers 102 and 103.The metallic catalyzing material will then sweep from the substrate 101or be mixed with the diamond layers 102, 103 or any combination thereof.After the sintering step is completed, the metallic catalyzing materialis removed from the second polycrystalline diamond layer 103, includingthe areas of the compact adjacent to the working surface 104. A varietyof techniques are employed to remove this metallic catalyzing materialas previously described in relation to FIG. 2. After removal of themetallic catalyzing material from the second polycrystalline diamondlayer 103, one or more non-metallic catalyzing materials or elements arereintroduced to the working surface 104 and the second polycrystallinediamond layer 103. Again, the present techniques for reintroduction ofthe catalyzing materials are described in relation to FIG. 2.

FIG. 4 shows a typical drill bit 400 with the compacts 100 of thisinvention incorporated therein. The fixed cutter drill bit 400 of thisFIG. 4 comprises a bit body 402 having a leading face 403 and a shank404 to permit the drill bit 400 to be secured to the remainder of adrill string (not shown). The bit body 402 is intended to be rotated, inuse, about an axis of rotation 401. Upstanding from the leading face 403are a plurality of blades 405 upon which a plurality of compacts orcutters 100 are mounted.

In alternative embodiments of the invention, a combination of one ormore of the features of the foregoing PDC devices should be consideredwithin the scope of this invention. Moreover, in alternative embodimentsthe various enumerated steps of the manufacturing process of the PDCdevices of this invention can be performed in various and differentorders, with some steps combined and other steps added without departingfrom the concept of this invention. The appended claims are to definethe scope of this invention. All process and devices that come withinthe meaning and range of equivalency of the claims are to be embraced asbeing within the scope of this patent.

1. A polycrystalline diamond compact, comprising: a volume of diamondmaterial having a top surface and a side surface, the volume of diamondmaterial including a material comprising cobalt in a first distinctregion of the volume of diamond material and a material comprisingcopper in a second distinct portion of the volume of diamond material.2. The polycrystalline diamond compact of claim 1, further comprising asubstrate, wherein the volume of diamond material is attached to thesubstrate.
 3. The polycrystalline diamond compact of claim 2, whereinthe substrate comprises cobalt.
 4. The polycrystalline diamond compactof claim 1, wherein the first distinct region includes at least aportion of the top surface.
 5. The polycrystalline diamond compact ofclaim 4, wherein the first distinct region includes at least a portionof the side surface.
 6. The polycrystalline diamond compact of claim 5,wherein the first distinct region includes substantially the entire topsurface.
 7. The polycrystalline diamond compact of claim 1, wherein thefirst distinct region includes at least a portion of the side surface.8. A process for making a polycrystalline diamond compact, comprising:sintering a volume of diamond material; defining a first region of thesintered polycrystalline diamond material such that it contains amaterial comprising cobalt; and defining a second region of the sinteredpolycrystalline diamond material such that it contains a materialcomprising copper.
 9. The process according to claim 8, furthercomprising attaching a substrate to the volume of diamond material. 10.The process according to claim 9, further comprising forming thesubstrate from a material comprising cobalt.
 11. The process accordingto claim 9, further comprising defining the second region to include atleast a portion of a top surface of the compact.
 12. The processaccording to claim 11, further comprising defining the second region toinclude at least a portion of a side surface of the compact.
 13. Theprocess according to claim 8, wherein sintering a volume of diamondmaterial further includes sintering the volume of diamond materialincluding introducing cobalt into both the first region and the secondregion, and wherein the method further comprises removing cobalt fromthe second region and subsequently introducing the material comprisingcopper into the second region.
 14. The process according to claim 13,wherein removing cobalt from the second region further includes leachingthe cobalt from the second region.
 15. A drill bit, comprising: a shank;and a bit body attached to the shank; at least one polycrystallinediamond compact attached to the body, wherein the at least onepolycrystalline body comprises: a substrate; and a volume of diamondmaterial having a top surface and a side surface, the volume of diamondmaterial including a material comprising cobalt in a first distinctregion of the volume of diamond material and a material comprisingcopper in a second distinct portion of the volume of diamond material.16. The drill bit of claim 15, further comprising a substrate, whereinthe volume of diamond material is attached to the substrate.
 17. Thedrill bit of claim 16, wherein the substrate comprises cobalt.
 18. Thedrill bit of claim 15, wherein the first distinct region includes atleast a portion of the top surface.
 19. The drill bit of claim 15,wherein the first distinct region includes at least a portion of theside surface.
 20. The drill bit of claim 15, wherein the first distinctregion includes substantially the entire top surface.
 21. The drill bitof claim 15, wherein the first distinct region includes at least aportion of the side surface.